W912DW25R0018_LWSC ECS_Site Visit Presentation_20250617.pdf
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- Solicitation number
- W912DW25R0018
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This document is a site visit presentation for the Lake Washington Ship Canal Emergency Closure System project at the Hiram M. Chittenden Locks (Ballard Locks) in Seattle, Washington. The presentation details the planned replacement of the existing emergency closure system, which was originally constructed in 1917 and has never been used. The new system features a full-height bulkhead with vertical storage, designed to be easily installed and rotated for maintenance, utilizing advanced 3D modeling to optimize the complex design.
Key technical features include a storage frame mounted on the monolith, allowing about 10 feet of gate to be submerged, and the ability to lift and drop the bulkhead vertically into a recess. The design addresses limitations of the current system, which requires divers to install, cannot be placed in flowing water, and has sealing and crane size issues. The project serves multiple purposes for the Hiram M. Chittenden Locks, including navigation between Puget Sound and local lakes, maintaining a salt water barrier, and regulating lake levels that support critical infrastructure like the SR-520 and I-90 floating bridges.
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| W912DW25R0018R0001_LWSC ESC_Amendment_20250624.pdf |
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Text version
HIRAM M. CHITTENDEN LOCKS
SMALL LOCK
EMERGENCY CLOSURE SYSTEM
JUNE 17,2025
Eric Flickinger, PE Tetra Tech Project Manager Chris Willcox, PE SE Tetra Tech Lead Structural Engineer
(BALLARD LOCKS)
Two locks:
Small Lock 30 x 150 ft Large Lock 80 x 825 ft 235-foot Dam Spillway Fish ladder
SMALL LOCK
• Cycles up to 50 times per day (summer)
• About 10,000 lockages per year
• More than any lock chamber in the nation
Lock Project Serves Several Purposes
• Navigation from Puget Sound to Lake Union and Lake Washington
• Salt Water Barrier
• Regulate Lake Levels
• (520 and 1-90 Floating Bridges)
Purpose - Regulate Lake Levels
I-90 Floating Bridge
520 Floating Bridge
• Lake Washington Floating Bridges
• Longest Floating Bridges in the World
• 520 Constructed in 2016 ($4.5B)
• Adding light rail to I-90
Existing Emergency Closure System Constructed in 1917 as part of Original Lock Construction Has never been used
Existing Emergency Closure System An emergency closure structure is any device designed to be placed in rapidly flowing water under differential head to prevent the loss of pool if the lock miter gates are damaged and can no longer function to control the pool.
• 5 Stoplogs
• Requires Divers to Install
• Cannot be Placed In
Flowing Water
• Seals Leak
• Cannot be used as a work gate
• Crane Undersized
Vertical Storage
• Storage frame mounted to top of monolith (no in-water construction)
• About 10 feet of gate is submerged
• Easy to install - lift vertically and drop in recess
Key Features
• Storage and Ease of Use Critical Factors
• Full height bulkhead with vertical storage is easier to use as a working gate and as an emergency bulkhead
• Larger crane can be beneficial for other maintenance activities
Key Features Continued…
• Provided bulkhead pipe support and storage frame saddles.
• Allows bulkhead to rotate horizontal for minor routine inspection/maintenance.
• Corrosion Protection System with magnesium anodes designed by Norton Corrosion.
• Complicated Geometry
• Multiple Positions
• Rotation
• Maintenance Position
3D Modeling
Much Easier with 3D Fewer Errors
Design with 3D Modeling
Bulkhead fits on support frame at multiple locations and allows rotation on support pins.
Bulkhead supported on trunions
Bulkhead being rotated
Bulkhead in maintenance position
| Hiram M. Chittenden Locks Small Lock �Emergency Closure System�June 17,2025 |
| Hiram M. Chittenden Locks �(Ballard Locks) |
| Hiram M. Chittenden Locks |
| Hiram M. Chittenden Locks �Small Lock |
| Lock Project Serves Several Purposes |
| Purpose - Regulate Lake Levels |
| Existing Emergency Closure System |
| Existing Emergency Closure System |
| Vertical Storage |
| Key Features |
| Key Features Continued… |
| Slide Number 12 |
| Slide Number 13 |
| Slide Number 14 |
| Slide Number 15 |
| Slide Number 16 |
File details come from the government source that posted it. Updated .